This page explains how Walter Witkowski (USATT# 21983)'s rating went from 905 to 855 at the California State Championship 2017 held on 5 May 2017 - 7 May 2017. The links below take you to pages that describe various aspects of the rating processor.

The rating processor goes through 4 passes in order. The links take you to pages that provide detailed explanations of the calculations during each of the 4 passes.